METHODS OF FORMING INTEGRATED CIRCUIT DEVICES USING CUTTING TOOLS TO EXPOSE METALIZATION PADS THROUGH A CAP STRUCTURE AND RELATED CUTTING DEVICES
A method of fabricating a semiconductor device can include providing an integrated circuit electrically coupled to a metallization pad on a semiconductor wafer, the integrated circuit and the metallization pad covered by a cap structure. A channel can be cut in a portion of the cap structure that covers the metallization pad using a cutting tool having a tip surface and a beveled side surface to expose an upper surface of the metallization pad in the channel extending in a first direction and a conductive material can be deposited in the channel to ohmically contact the upper surface of the metallization pad in the channel.
The present invention relates generally to electronic devices. More particularly, the present invention provides techniques related to a method of manufacture and a structure for bulk acoustic wave resonator devices, single crystal bulk acoustic wave resonator devices, single crystal filter and resonator devices, and the like. Merely by way of example, the invention has been applied to a single crystal resonator device for a communication device, mobile device, computing device, among others.
Wireless data communications can utilize RF filters operating at frequencies around 5 GHz and higher. It is known to use Bulk acoustic Wave Resonators (BAWR) incorporating polycrystalline piezoelectric thin films for some applications. While some polycrystalline based piezoelectric thin film BAWRs may be adequate for filters operating at frequencies from about 1 to 3 GHz, applications at frequencies around 5 GHz and above may present obstacles due to the reduced crystallinity associated with such thin poly-based films.
SUMMARYA method of fabricating a semiconductor device can include providing an integrated circuit electrically coupled to a metallization pad on a semiconductor wafer, the integrated circuit and the metallization pad covered by a cap structure. A channel can be cut in a portion of the cap structure that covers the metallization pad using a cutting tool having a tip surface and a beveled side surface to expose an upper surface of the metallization pad in the channel extending in a first direction and a conductive material can be deposited in the channel to ohmically contact the upper surface of the metallization pad in the channel.
According to the present invention, techniques generally related to electronic devices are provided. More particularly, the present invention provides techniques related to a method of manufacture and structure for, for example, bulk acoustic wave resonator devices, single crystal resonator devices, single crystal filter and resonator devices, and the like. These types of devices have been applied to a single crystal resonator device for communication devices, mobile devices, and computing devices, among others. It will be understood, however, that embodiments according to the invention, may be applied to any manufacturing process involving the singulation of devices fabricated on a wafer, regardless of the technology or application.
As appreciated by the present inventors, a cutting tool can be used to expose metallization pads of integrated circuit devices located on a wafer. In some embodiments, the cutting tool can be shaped to cut a channel through a wafer cap structure that is configured to reduce the likelihood of forming a void when depositing conductive material on the metallization pads that are exposed in the channel. For example, in some embodiments according to the invention, the cutting tool has a beveled side surface and a flat tip surface that can, when cutting the wafer cap, form the channel to expose the upper surface of metallization pads. The channel can therefore be formed to have beveled side walls that are tapered outward so that channel is wider at the top than at the bottom. As further appreciated by the present inventors, this tapered channel shape can allow improved contact between the deposited conductive material and the metallization pads when the conductive material is deposited on the pads.
In some embodiments, the beveled side surface of the cutting tool can form an angle with the tip surface that is in a range between about 60 degrees to about 85 degrees. In some embodiments, the cutting tool is wide enough to expose metallization pads of two adjacent devices on the wafer in a single pass and has opposing beveled side surfaces to impart a corresponding beveled side wall surface for each side of the channel adjacent to each device. In some embodiments, the cutting tool is wide enough to expose the metallization pads in a single row of metallization pads of a device in a single pass and has opposing beveled side surfaces to impart a corresponding beveled side wall surface for each side of the channel for that single row.
In some embodiments, the beveled side surface of the cutting tool can be a single beveled surface. For example, in some embodiments, the beveled side surface can have a height that is about equal to the depth that the cutting tool will cut into the wafer cap structure. In some embodiments, the beveled side surface of the cutting tool include two or more beveled side surfaces. In some embodiments, the beveled side surface can have a lower portion with a height that is about 50% of the depth that the cutting tool will cut into the wafer cap structure. In still further embodiments, the beveled side surface can have a first beveled portion that is beveled at a first angle and a second beveled portion that is beveled at a second angle.
In some embodiments, the cutting tool can be used to cut the wafer cap structure for a plurality of devices arranged in a first direction on the wafer. In some embodiments, the cutting tool can be used to cut the wafer cap structure for a plurality of devices arranged in first direction and second directions on the wafer. In some embodiments, the cutting tool can include more than one cutting portion where each portion is configured to cut a channel to expose the metallization pads for a different device on the wafer.
In some embodiments according to the invention, however, a cutting device can be used to cut into a wafer cap structure that covers the integrated circuit device to expose the metallization pads of the device rather than to cut through the wafer. In other words, the cutting tool that may be used to singulate the devices by cutting along the scribe areas may also be used to cut into the devices that are located between the scribe areas.
It will be understood that the integrated circuit devices shown in
It will be further understood that a cutting device saw is used to dice the wafer into pieces to separate the devices from one another. In some embodiments, according to the mentioned comma, however, the cutting device can be used to cut the wafer cap structure that covers the integrated circuit device to expose the metallization pads that are used to conduct signals to and from the integrated circuit device.
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It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the various embodiments described herein. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items,
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting to other embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including”, “have” and/or “having” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Elements described as being “to” perform functions, acts and/or operations may be configured to or other structured to do so.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments described herein belong. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, shall support claims to any such combination or subcombination.
Claims
1. A method of fabricating a semiconductor device, the method comprising:
- providing an integrated circuit electrically coupled to a metallization pad on a semiconductor wafer, the integrated circuit and the metallization pad covered by a cap structure;
- cutting a channel in a portion of the cap structure that covers the metallization pad using a cutting tool having a tip surface and a beveled side surface to expose an upper surface of the metallization pad in the channel extending in a first direction; and
- depositing a conductive material in the channel to ohmically contact the upper surface of the metallization pad in the channel.
2. The method of claim 1 wherein the tip surface and a portion of the beveled side surface, that is adjacent to the tip surface, form an angle in a range between about 60 degrees to about 85 degrees.
3. The method of claim 2 wherein the metallization pad has a thickness in a range between about 1.5 microns to about 2 microns.
4. The method of claim 3 wherein the beveled side surface forms a beveled side wall in the channel relative to the upper surface of the metallization pad.
5. The method of claim 1 wherein a height of the beveled side surface is at least about 50% of a thickness of the cap structure.
6. The method of claim 5 wherein a side surface of the cutting tool above the beveled side surface and the tip surface form an angle that is in a range between about 60 degrees to about 90 degrees.
7. The method of claim 1 wherein the channel has a width that exposes at least about 20% of the upper surface of the metallization pad.
8. The method of claim 1 wherein cutting the channel in the portion of the cap structure comprises moving the cutting tool across the semiconductor wafer within the cap structure to form the channel exposing the upper surface of the metallization pad.
9. The method of claim 1 wherein the cutting tool comprises a rotating blade or a rotating wire.
10. The method of claim 1 wherein a thickness of the cap structure is in a range between about 50 um to about 100 um.
11. The method of claim 1 wherein the cap structure comprises glass or polymer material.
12. The method of claim 1 wherein providing the integrated circuit electrically coupled to the metallization pad on the semiconductor wafer comprises:
- providing the integrated circuit electrically coupled to a first metallization pad on the semiconductor wafer and a second metallization pad that is electrically coupled to the integrated circuit; and
- wherein cutting the channel in the portion of the cap structure comprises moving the cutting tool across the semiconductor wafer in the first direction within the cap structure to form the channel exposing the upper surface of the first metallization pad and an upper surface of the second metallization pad.
13. The method of claim 12 wherein the integrated circuit comprises a first integrated circuit, the method further comprising:
- a second integrated circuit, separated from the first integrated circuit in the first direction on the semiconductor wafer, the second integrated circuit electrically coupled to a third metallization pad, aligned to the first and second metallization pads in the first direction and covered by the cap structure, on the semiconductor wafer; and
- wherein cutting the channel in the portion of the cap structure comprises moving the cutting tool across the semiconductor wafer in the first direction within the cap structure to form the channel exposing the upper surface of the first metallization pad, the upper surface of the second metallization pad, and the upper surface of the third metallization pad; and
- depositing the conductive material in the channel to ohmically contact the upper surfaces of the first, second, and third metallization pads in the channel.
14. The method of claim 1 wherein the integrated circuit comprises a first integrated circuit electrically coupled to the metallization pad comprising a first metallization pad and covered by the cap structure comprising a first cap structure, the method further comprising:
- a second integrated circuit, separated from the first integrated circuit in a second direction orthogonal to the first direction on the semiconductor wafer, the second integrated circuit electrically coupled to a second metallization pad and covered by a second cap structure, on the semiconductor wafer; and
- wherein cutting the channel in the portion of the cap structure comprises moving the cutting tool across the semiconductor wafer in the first direction within the first and second cap structures between the first and second integrated circuits to form the channel exposing the upper surface of the first metallization pad and an upper surface of the second metallization pad; and
- depositing the conductive material in the channel to ohmically contact the upper surfaces of the first and second metallization pads in the channel.
15. The method of claim 14 wherein the beveled side surface of the cutting tool comprises a first beveled side surface facing the first integrated circuit, the cutting tool further comprising:
- a second beveled side surface facing the second integrated circuit, wherein the tip surface extends from the first beveled side surface to the second beveled side surface.
16. The method of claim 15 wherein the tip surface and a portion of the first beveled side surface, that is adjacent to the tip surface, form a first angle in a range between about 60 degrees to about 85 degrees and wherein the tip surface and a portion of the second beveled side surface, that is adjacent to the tip surface, form a second angle in a range between about 60 degrees to about 85 degrees.
17. The method of claim 16 wherein the channel has a width that exposes at least about 20% of the upper surface of the first metallization pad and about 100% of the upper surface of the second metallization pad.
18. The method of claim 1 wherein ohmic contact between the conductive material in the channel and the upper surface of the metallization pad a specific contact resistivity of less than about 10 e-03 ohm2.
19. An apparatus comprising:
- a cutting tool having a tip surface and first and second beveled side surfaces on opposite sides of the tip surface, the first and second beveled side surfaces each defining an angle with the tip surface in a range between about 60 degrees to about 85 degrees.
20. The apparatus of claim 19 wherein a width across the tip surface is selected to be less than about a width of a metallization pad to about a spacing between integrated circuit devices plus two times a width of the metallization pad.
Type: Application
Filed: Feb 7, 2020
Publication Date: Aug 12, 2021
Patent Grant number: 11348798
Inventors: Robert C. Dry (Cornelius, NC), Brook Hosse (Huntersville, NC)
Application Number: 16/784,912